The stage of cancer describes to what extent, or how far, the cancer has spread. By using exams and tests, a doctor can determine the stage of your cancer.
There are different staging systems used for cancer. Most cancers are staged with the Roman numerals I, II, III, and IV, based on whether the cancer is still contained within the area where it began, has started to spread into nearby tissues and/or organs, or has spread to more distant tissues and/or organs. Stage I is the earliest stage and usually means the cancer is still contained in the initial area of origin and hasn't spread. Stage IV is the most advanced stage, where cancer has spread far from the original site of development.
If you have been diagnosed with carcinoma of unknown primary origin (CUP), your cancer has spread from an unknown origin. Thus, you are considered to have advanced metastatic cancer, and by definition, the stage of your cancer is at least a stage II. It is likely that your cancer is a stage III or IV. If you have only a single site of known cancer, local treatments such as surgery and radiation therapy may help.